Agricultural combines are available in various designs and models to perform the basic functions of reaping crop materials from a crop field, separating the grain from the non-grain crop materials, and discarding the non-grain crop materials back onto the crop field.
A typical combine includes a crop harvesting apparatus, or header, which reaps ripened crop plants from the field and feeds the crop materials to a separating or threshing system. Several different types of threshing systems are available, such as rotary threshers and straw walkers. Regardless of the type of threshing system used, the thresher generally operates to separate the materials other than grain (MOG) from the grain heads. The MOG primarily consists of grain stalks and exits the thresher along its rear end. The grain exits along the bottom side of the thresher and passes to a series of moving sieves that separate the grain from the unwanted fine materials, sometimes referred to as chaff. After separation, the grain is directed to a grain bin by an auger system, and the unwanted fine materials exit the sieves along the rear end of the combine.
The grain bin serves as a temporary onboard storage location for the grain. Typically, the grain bin is positioned above the threshing system and can have a capacity of as much as 200 bushels or more for larger combines. As the combine harvests the crop field, the grain bin periodically becomes filled with grain and must be emptied to allow the combine to further operate. The grain is transferred from the grain bin to a truck or a grain cart through an unloading auger.
In a common configuration, the unloading auger is positioned along the upper side of the combine with an infeed section of the auger located adjacent to the grain bin and pivotally attached to the combine to allow rotation about a nearly vertical axis. An elbow connects the infeed section to a long horizontal section that can rotate in a generally horizontal plane around the infeed section to allow unloading of the grain into a truck or grain cart located alongside the combine. After unloading, the unloading auger is rotated back so that the horizontal section trails towards the rear of the combine with the exit end of the auger located near the combine's back end.
As combines grew larger, the relatively longer length of the unload auger horizontal section became problematic for manufacturers and operators alike. A solution was developed to effectively increase the length of the horizontal section during unloading, yet maintain a shorter, compact configuration in the stored/transport position of the unload auger. The horizontal section was defined by folding auger segments that could pivot relative to each other from a folded position into an in-line operational position, with drive couplers configured at the hinged joint between the respective folding segments. Reference is made, for example, to U.S. Pat. No. 6,908,380 for a discussion of such a system.
With a known type of drive coupler between the folding auger segments, a single drive lug or cog on a driver component rotationally engages a single tooth or cog on the driven component. This arrangement is beneficial in that it effectively rotationally disconnects the downstream auger segments for about a full revolution of the driver, thereby limiting the starting torque and allowing the driver component to generate some degree of rotational momentum prior to engaging the driven auger segment. In addition, this arrangement allows the augers to always be properly timed with respect to each other. By having only one cog or lug on each auger segment, the segments will have the same orientation with respect to each other every time the system is engaged.
The single cog auger segment arrangement, however, also has inherent drawbacks. Upon engaging the unload system, a relatively loud mechanical “clunk” noise is generated when the driver cog impacts the driven cog, which can be disconcerting to some operators. In addition, a significant and sudden torque spike is generated when the cogs impact, which induces stresses along the entire auger dive train.
Thus, the industry would benefit from an unload auger that maintains the benefits of the single driver cog/driven cog coupler while eliminating the inherent drawbacks of such coupler.